package com.desire.test;

/**
 * @author desire
 */
public class _11_字符串实例 {
    public static void main(String[] args) {
        StringBuilder str = new StringBuilder("54147857148587");
        for (int i = str.length() - 3; i > 0; i -= 3) {
            str.insert(i, ", ");
        }
        System.out.println(str);
    }
}
